镍渣资源化利用现状及发展趋势分析

镍渣含Fe 40%~45%,SiO_232%~36%,MgO 1%~11%,CaO 1%~3%(质量分数),并含少量的镍、铜、钴等有价金属,是重要的二次资源。介绍了典型镍渣成分及物相,总结了镍渣提取有价金属、作井下填充材料、生产微晶玻璃、制备建材等资源化利用工艺的技术要点,分析了现有工艺存在的问题,提出了镍渣直接还原提铁及协同制备胶凝材料的绿色利用思路,介绍了初步研究结果,探讨了进一步资源化的方向。     

Effect of postmolding heat treatment on in vitro properties of a polyanhydride implant containing gentamicin sulfate

A polyanhydride implant containing gentamicin sulfate was fabricated using a laboratory-scale injection-molding machine. After injection molding, the implants were subject to heat treatment at 60°C for various time periods with or without nitrogen protection. The impact of this heat treatment on the in vitro properties of the implants including copolymer molecular weights, mechanical properties, and in vitro drug-release profiles was investigated. This heat treatment caused a drastic drop in the molecular weight of the copolymer. Heating without nitrogen protection resulted in the hardening of the implant, but heating in the presence of nitrogen rendered the implant less rigid. It was also found that a faster in vitro drug release profile was shown by implants heated without nitrogen protection and a pronounced slowing down in drug release was exhibited by implants heated with nitrogen protection.     

Central composite rotatable design for optimization of budesonide-loaded cross-linked chitosan–dextran sulfate nanodispersion: characterization,in vitro diffusion and aerodynamic study

Budesonide is a BCS class II drug with low water solubility (0.045?mg/mL) and low oral bioavailability (6–8%) due to high first pass effect. The aim is to prepare cross-linked chitosan–dextran sulfate nanoparticles and/or nanodispersion. Nebulizable cross-linked nanodispersion was prepared by the solvent evaporation technique and characterized through XRPD, FTIR, mean particle size (MPS), polydispersity index (PDI), zeta potential (ZP), drug loading, entrapment efficiency, SEM, % production yield, in vitro diffusion, aerodynamic and stability study. The optimization of formulation was done by using central composite rotatable design to study the effect of independent variables, concentration of chitosan (X1) and concentration dextran sulfate (X2) on the dependent variables, MPS (Y1), drug loading (Y2) and % CDR (% cumulative drug release) (Y3). The MPS, PDI, and ZP of budesonide-loaded nanoparticles were 160.8?±?0.27?nm, 0.36?±?0.04, and 13?±?0.894?mV, respectively. The percent drug loading of all the batches was found in range of 10–16%. The emitted drug in target region (alveoli) was measured by using HPLC and it was found to be 18.26%. It was found that, nanodispersion had the optimum in vitro aerodynamic behavior. Stability study results showed no significant change in MPS, PDI, ZP, and % CDR after three month storage. In conclusion, cross-linked chitosan–dextran sulfate nanoparticles had properties suitable for nebulizable dispersion of increased drug loading, in vitro drug release and avoiding the first pass effect.     

填料特性对导电性复合材料性能的影响

使用碳纤维与镍粉组成混合填料加入低密度聚乙烯中，研究，材料性能的变化规律，结果发现，以等体积的碳纤维取代镍粉，未必能提高导电能力，其中沥青系碳纤维在大部或全部取代了镍后，电阻率还显著增加，只有当填料总的体积含量显著增加时，导电性才能进一步提高，纤维的加一般增加了拉伸强度，却降低了冲击强度，而且在含量不太高的情况下，含聚丙稀腈碳纤维材料的强度优于含沥青纤维的材料。     

新的多孔泡沫镍制备工艺

针对目前泡沫金属制备方法的缺点,提出了一种泡沫金属制备的新方法——电解液喷射沉积法。研究了喷射沉积制备泡沫镍的工艺,自行研制了试验装置,制备了具有不同孔隙率的泡沫镍试样,分析了相关工艺参数(电解液成分、电流密度、电解液喷射速度等)对泡沫镍微观结构的影响。结果表明:采用相对较低的镍离子浓度配方Bath A对制备均匀致密的枝晶多孔结构有利。随着电流密度的提高,泡沫镍的孔隙率逐渐降低;随着电解液喷射速度的提高,泡沫镍的孔隙率逐渐增加。总体上采用电解液喷射沉积法制备的泡沫镍的孔隙率在30~70%之间。     

纳米凹凸棒石的化学镀镍

以天然凹凸棒石矿物为原料,分散提纯获得纳米纤维凹凸棒石,并利用化学镀镍技术对纳米凹凸棒石进行改性.采用透射电子显微镜(TEM)和X射线衍射(XRD)分析研究预处理工艺对纳米凹凸棒石化学镀镍的影响.结果表明:通过镀前预处理以增加凹凸棒石表面的活化点,能够在凹凸棒石表面实现化学镀镍,但由于纳米凹凸棒石长径比较大,反应活性低...     

镀镍碳纳米管的微波吸收性能研究

用竖式炉流动法制备了碳纳米管,碳纳米管的外径40nm～70nm,内径7nm～10nm,长度50μm～1000μm,呈直线型,用化学镀法在碳纳米管表面镀上了一层均匀的金属镍。碳纳米管吸波涂层在厚度为0.97mm时,在8GHz～18GHz,最大吸收峰在11.4GHz(R=-22.89dB),R<-10dB的频宽为3.0Hz,R<-5dB的频宽为4.7GHz。镀镍碳纳米管吸波涂层在相同厚度下,最大吸收峰在14GHz(R=-11.85dB),R<-10dB的频宽为2.23Hz,R<-5dB的频宽为4.6GHz。碳纳米管表面镀镍后虽然吸收峰值变小,但吸收峰有宽化的趋势,这种趋势对提高材料的吸波性能是有利的。碳纳米管作为偶极子在电磁场的作用下,会产生耗散电流,在周围基体作用下,耗散电流被衰减,从而雷达波能量被转换为其它形式的能量。     

Investigation of small fatigue crack initiation and growth behaviour of nickel base superalloy GH4169

Surface replication method was utilized to monitor the small fatigue crack initiation and growth process of single‐edge‐notch tension specimens fabricated by nickel base superalloy GH4169. Three different stress levels were selected. Results showed that small fatigue cracks of nickel base superalloy GH4169 initiated from grain boundaries or surface inclusions. The small fatigue crack initiation and growth stages took up about 80–90% of the total fatigue life. Multiple major cracks were observed in the notch root, and specimen with more major cracks seemed to have smaller fatigue life under the same test conditions. At the early growth stage, small crack behaviour might be strongly influenced by microstructures; thus, the crack growth rates had high fluctuations. However, the stress level effect on the small fatigue crack growth rates was not distinguishable for the three different stress levels. And no clear differences were found among the crack initiation lives by using replication technique.     

硫酸钾尾液冷冻回收高硫钾比矿物工艺研究

以硫酸钾尾液为原料,研究低温冷冻回收高硫钾比矿物合理的工艺技术路线,探寻适宜的贮存条件,为加工车间夏季高温生产硫酸钾提供优质高硫钾比原料.在低温下进行冷冻试验,根据冷冻结晶矿物产率及其干基组分确定适宜的冷冻温度为-15～5℃,冷冻制得的结晶矿物硫钾比均在3.0～5.1,符合夏季生产硫酸钾所需原料硫钾比>2.5的要求.高...     

超声波辅助下中低温化学镀镍工艺的研究

为降低化学镀镍的施镀温度,提高化学镀镍的沉积速度,将超声辐射引入化学镀镍工艺当中,对超声波辅助下的中低温化学镀镍工艺作了初步的探讨.着重考察了配体、稳定剂以及超声波对化学镀镍的影响.实验结果表明,超声波对化学镀镍沉积速度的作用与镀液中镍离子络合物的稳定常数(pK)有关,在温度为60℃的中低温条件下,以醋酸钠为配体的化学镀镍溶液中,超声波具有明显促进沉积速度的作用,但随着稳定常数的增大,超声波反而对沉积速度起抑制作用.